2835 pro s is a bolt-on, if you buy the kit, it fits perfectly and comes with the dump pipe already. didnt take me long to install mine the only problem i found was that when tring to tighten the bolts that connect the turbo to the manifold it was tight fit to get the socket in there.
Also you dont need a dump pipe gasket if you but the KIT, as after tring to find one for my kit, i ended up calling HKS and after them sending me the wrong gasket 2times they told me they made a mistake and the gt2835 pro s kits dont need a gasket at all, ive been running mine for almost a year without a gasket and no problem at all!
internal gate is ok! lol ive got one, much cheaper going internal too
R33, my engine internals are all stock, my engine has done 100,000km and i made 350hp @ 16psi without a problem